Knitting machine presser edge



Pl'l 22, 1952 J. H. couLLlETTE 2,594,128

Patented Apr. 22, 1952 KNITTING MACHINE PnEssEa EDGE .ames H. Coulliette, Chattanooga, Tenn., assignor to Industrial Research Institute of the University of Chattanooga, Chattanooga, Tenn.

Application March 1, 1951, Serial No. 213,369

6 Claims.

This invention relates generally to knitting machines and the like and has especial reference to an improved sinker-head for reducing needle Wear.

In operating knitting machines it has been found that needles, rubbing against the presser edges of sinker-heads are worn thin in a few Weeks or months in some cases whereas other presser edges can be used for several years without causing excessive needle wear, even though the sinker-heads in question may be on the same machine. In investigating this erratic behavior I have found, through making photomicrographs of the presser edge surfaces, that the sinkerheads causing excessive or unusual needle wear seem to contain inclusions of microscopic or larger abrasive particles which are believed to be the principal cause of excessive wear of the needles. These pa-rticles may be various types of foreign matter, crystals, alloy aggregates, or other substances.

It is, therefore, an object of my invention to provide an improved sinker-head having a relatively smooth and non-abrasive presser edge, in order to reduce needle Wear appreciably.

Another object is to provide sinker-heads Which can readily be made from unsatisfactory sinker-heads at moderate cost.

A further object is to provide sinker-heads which can repeatedly be treated or processed to make them satisfactory for use again.

Other objects will be evident in the specification.

The drawing is a fragmentary, perspective view of a sinker-head and associated needles and knitting. The sinker-head I has presser edge 2 against which beards 3 of needles 4 are pressed as the needles are pulled down, thereby forming closed loops around yarn 5 to pull it through the knitted loops 6 of the yarn. Knockover bits 'l are showualso.

In the prior art sinker-heads have usually been made of brass and the needles of steel. Much trouble has been encountered however in the beards of the needles wearing away, in a few weeks in many cases. From photomicrographic studies I have made it appears that this rapid Wear is due to abrasion of the steel needle, or beard, in contact with the brass presser edge, due to the inclusion of abrasive particles of foreign matter in the metal from which the presser edge is formed. In order to reduce and largely to eliminate this abrasive action, I plate or other- Wise coat the presser edge metal with a layer of silver, tin, lead, or an alloy of these or similar metals, to provide a relatively soft, abrasive-free metal surface against which the needle or beard can be rubbed with a minimum of wear. Various alloys can be used such as silver-tin, lead-tin. silver-lead; or the pure metals can be used as coatings.

Electroplating can be employed to cover the metal forming the presser edge with a silver, tin, or other suitable coating approximately several thousandths of an inch thick. This ccating is heavy enough to cover any microscopic or minute abrasive particles at the presser edge surface but thicker coatings can of course be used; As an alternative a relatively thin plate of silver, alloy, tin, or the like can be screwed or otherwise fastened to the presser edge of the sinker-head in order toJ reduce needle wear. If desired, the metal of the sinker-head can be cut back for a distance equal to the thickness of the added plate. Electroplating is, however, a satisfactory method for coating abrasive presser edges and is relatively inexpensive. By means of this coating method slinker-head presser edges can be manufacturecl for longer wear, abrasive presser edges now in use can be treated to increase the working life of needles greatly, and expensive shutdowns of machinery can be avoided.

While I have described specific embodiments of my invention, it is obvious that others skilled in the art can make changes of detail without departing from the principles I have disclosed.

What I claim is:

1. In a knitting machine, an element cooperating with a needle rubbed over a surface thereof, said surface being covered with relatively abrasive-free metal softer than the metal of said needle.

2. In a knitting machine, a sinker-head having a presser edge adapted to be rubbed by a needle, said presser edge being coated with metal of softer and less abrasive character than the metal of said sinker-head.

3. In a knitting machine, a sinker-headl having a presser edge adapted to be rubbed by a needle, said presser edge being coated with material comprising tin.

4. In a knitting machine, a sinker-head having a presser edge adapted to be' rubbed by a needle, said presser edge being coated with material comprising silver.

5. In a knitting machine, a sinker-head having a presser edge adapted to be rubbed by a needle, said presser edge being coated with material comprising lead.

6. In a knitting machine, a brass sinker-head having a presser edge adapted to be rubbed by a needle, said presser edge being coated with a relatively abrasive-free metal of softer character than said brass.

JAMES H. COULLIE'I'I'E.

REFERENCES CITED UNITED STATES PATENTS Name Date Richter Apr. 11, 1939 Number 

